The present invention relates to semiconductor devices and manufacturing methods of semiconductor devices, and more particularly, to a semiconductor device with a magnetoresistive element, and a manufacturing method of the semiconductor device.
Conventionally, a dynamic random access memory (DRAM) and a static random access memory (SRAM) are widely used as semiconductor devices, including a semiconductor integrated circuit for memory. On the other hand, a magnetic random access memory (MRAM) is a device for storing information by use of a magnetic field. The MRAM has excellent characteristics of high-speed performance, rewriting resistance, nonvolatility, and the like, as compared to other memory technologies.
The MRAM includes magnetoresistive elements referred to as a magnetic tunnel junction (MTJ) element, which uses a tunneling magnetoresistive (TMR) effect. The MRAM stores information based on the magnetization state of the magnetoresistive elements. The magnetoresistive elements are positioned in an array at intersections between digit lines extending in one direction and bit lines extending in the direction substantially perpendicular to the direction of the digit line. Each magnetoresistive element is comprised of two magnetic layers laminated with a tunneling insulating film intervening therebetween. The magnetoresistive element includes a layer whose magnetization direction is changed by a magnetic field generated by current flowing between the digit lines and the bit lines. The magnetoresistive element stores therein the magnetization direction as the information. The magnetoresistive element has its electrical resistance changed according to the magnetization direction of the layer. The change in current flowing through the magnetoresistive element is sensed based on the change in electrical resistance to thereby detect the information stored in the magnetoresistive element. A magnetic tunnel junction element disclosed in, for example, Japanese Unexamined Patent Publication No. 2007-158361 (Patent Document 1) has been hitherto proposed as one example of such a magnetoresistive element used as a magnetic sensor.
As disclosed in, for example, Japanese Unexamined Patent Publication No. 2003-332651 (Patent Document 2), a magnetoresistive effect element has a structure having an etched region from an upper electrode to an intermediate part of a barrier layer sandwiched between a free layer and a fixed layer. The region is etched so as to have a smaller superficial area intersecting in the lamination direction than that of the fixed layer located under the intermediate part of the barrier layer.
[Related Art Documents]
[Patent Documents]
    [Patent Document 1]
Japanese Unexamined Patent Publication No. 2007-158361    [Patent Document 1]
Japanese Unexamined Patent Publication No. 2003-332651